If you use the "wrong" bill denominations or don't have the right coins, cashiers can get irked at you too. It's so backwards compared to not having to think about it.
Cashless is more convenient. But given how fundamental money is in our society, I would never be fine with a centralized system that controls all payments. That is simply too much power in one place. I know HN is more about startup-hackers than FOSS-hackers, but I am pretty sure everyone here understands that this is a dangerous development.
Yes, sometimes cashiers ask if I have certain coins to make giving change easier.
Also you need coins for shopping carts.
You would have encountered the identical behavior in the bay area if you'd paid for things in cash. That's not because the cashier expects you to have the coins; it's an extra effort on their part to make things more convenient for you.
Is this something you were doing before?
If not, why did you bring it up? Who do you imagine is doing this?